What your carrier already does
Phone companies block billions of unwanted calls a year. They may enroll you in call blocking automatically; you can opt out if you worry about missing wanted calls. Others label calls instead, with “spam” or “scam likely” on the caller ID. Depending on the carrier, a blocked call may go to voicemail, ring once with caller ID, or leave no trace at all.
If your carrier blocks calls based on its analytics, you can ask it for the list of calls it blocked to your number in the last 28 days. It must send the list, with dates, times and calling numbers, within three business days and at no charge.
Free tools from AT&T, Verizon and T-Mobile
| Carrier | Free | Paid option |
|---|---|---|
| AT&T | ActiveArmor, with every wireless plan: fraud calls blocked by default, spam calls labeled; you can block or send spam to voicemail. | Advanced features, $7 a month |
| Verizon | Call Filter on compatible phones: flags spam, robocalls and fraud, and sends high-risk spam to voicemail (data usage applies). | Call Filter Plus, $3.99 a month |
| T-Mobile | Scam ID labels and Scam Block blocks “Scam Likely” calls before they reach you. Without the T-Life app, dial #662# to turn Scam Block on. | Premium Scam Shield features |
From each carrier's own pages. One AT&T caveat: sending callers to voicemail needs an active voice mailbox, or calls from numbers outside your contacts will not get through.
iPhone
- Unknown callers: Settings, Apps, Phone, Screen Unknown Callers. “Silence” sends calls from unsaved numbers to voicemail; “Ask Reason for Calling” has your iPhone ask the caller why they are calling before it rings. Calls are not screened while you roam, and screening switches off for 24 hours after you call emergency services.
- Spam: calls your carrier identifies as spam or fraud are silenced, sent to voicemail and listed under Spam.
- One number: in the Phone app, tap Contacts, the contact, then Block Contact.
Android
- Spam: in the Phone by Google app, caller ID and spam protection is on by default. Turn on “Filter spam calls” to stop them ringing; they stay in your call history.
- Call Screen: find out who is calling and why before you pick up. Detected spam is declined without alerting you.
- One number: from your call history, tap the call, then Block or report spam. The phone then declines that number automatically.
Landlines
Ask your phone company what it offers; the FCC also points to apps and devices, many free or cheap. On Verizon home phones, Anonymous Call Rejection (*77) stops calls from hidden numbers from ringing. More on hidden numbers in No Caller ID calls.
What blocking cannot do
Verizon says it cannot guarantee every spam call is detected, and Google says not all spam calls and robocalls can be detected. The FTC adds the other side: call-blocking services might block some calls you want. For calls that get through, report them; reported numbers go to the companies that build these filters. See how to report a call.